1. Field of the Invention
The present invention relates to a band-gap reference voltage generator, and more particularly, to a band-gap reference voltage generator that can be miniaturized by reducing a size of a resistor occupying a large chip area and can provide a stable reference voltage lower than or equal to 1 V.
2. Discussion of Related Art
In general, all analog/radio frequency (RF) circuits or digital circuits manufactured with chips need a stable and accurate bias voltage for efficient operation. Therefore, a band-gap reference voltage generator is used to provide a stable reference voltage regardless of temperature variation.
However, a conventional band-gap reference voltage generator provides a reference voltage of about 1.25 V, it is not applicable to a circuit designed for applying a voltage lower than or equal to 1 V. There is a problem in that a power supply voltage of at least 1.5 V should be used to ensure smooth operation of transistors used in the reference voltage generator.
On the other hand, a small-area and low-power core chip design for guaranteeing portability and long lifespan is important in widely-used mobile communication terminals.
With the development of deep sub-micron CMOS technology, a small area and low power (or low voltage) may be implemented. However, there is a problem in circuit design since only a core band-gap bias circuit within a chip needs an operation voltage of at least 1.5 V when a low supply voltage is used for a low-power design.
To address this problem, a band-gap reference voltage generator for reducing a reference voltage to 1 V or less using a resistor has been proposed. However, this band-gap reference voltage generator has a problem of increased circuit area since a relatively large-sized resistor is needed.